Disabling mouse coordinates programmatically

[Glenn Golden]

When plotting with gnuplot, is it possible to programmatically do the 
equivalent of typing 'm' in the plot window to suppress display of the
mouse coordinates at the lower left?

More generally: Many years back, I seem to recall that Octave supported
some sort of informal mechanism by which commands could be sent to gnuplot.
Is that facility still available in some hidden way, or is it gone for good?